No. 10 - Discord
As you may see that we have seen Discord reform in Keep Calm and Flutter On but he has been appearing in episodes like The Return Of Harmony - Part 1, The Return Of Harmony - Part 2, Make New Friends But Keep Discord and so on. He has been so irritating and annoying but he isn't the worst villain...
No. 9 - Diamond Tiara
Well Diamond Tiara isn't a villain but a major antagonist. She has appeared in loads of episodes ever since. This earth pony deserves to be punched in the face! Bullying the CMC (cutie mark crusaders)
No. 8 - Sunset Shimmer
Sunset Shimmer appears in the movie, Equestria Girls. OK. We can see in the movie that she turns into a demon and now becomes good in mere seconds. But Sunset has been such a nuisance in the beginning, stealing Twilight Sparkle's crown...
No. 7 - Starlight Glimmer
For all the bronies who have seen The Cutie Map - Part 1 and 2, Starlight Glimmer has appeared in both episodes. Why, she has been totally stupid telling fibs about her fake cutie mark and revealing her real cutie mark. Stealing the Mane 6's cutie marks too. In Amending Fences, she has been seen sitting at the top left corner reading a newspaper. So actually she has made only 2 appearances.
No. 6 - Nightmare Moon
Nightmare Moon (Princess Luna) has been very nasty and has made lots and lots of appearances. Although she is Princess Luna, Nightmare Moon has been a total nuisance. She is one of my worst villains. Well, there is not much I can describe about her...
No. 5 - King Sombra
King Sombra has appeared in The Crystal Empire - Part 1 and 2 and has been performing dark magic ever since. I don't even know if he is a pony or not but he seems very bad... Hopefully he doesn't appear again...
No. 4 -[http:// Midnight Sparkle Midnight Sparkle]
Midnight Sparkle (Twilight Sparkle turned evil) looks like the next Nightmare Moon but in the human world. Now Sunset (who has turned good) will face the magic of Friendship towards Midnight Sparkle. She even sounds like Nightmare Moon!
No. 3 - Lord Tirek
Lord Tirek has been stealing magic and power from ponies! Uh, why do I even bother? He has been one of the worst villains in this list! I hate Lord Tirek...
No. 2 - Trixie
Trixie has made 2 major appearances in Boast Busters and Magic Duel. She has turned friendly but has been very mean ever since she arrived in Ponyville. She is an absolute show-off
No. 1 - The Mane-iac
The Mane-iac is the worst villain ever. Appearing in Power Ponies, she wants to take over the world! But that won't stop her! Her mane looks absolutely hideous...
My comment is that when you look on this page just don't mind my decisions and opinions. I am 10 years old but you know best. Just comment politely and try and include what I have missed out.
Hope you've enjoyed!